If you know your gun likes a certain brand in FMJ...

This is a discussion on If you know your gun likes a certain brand in FMJ... within the Defensive Ammunition & Ballistics forums, part of the Defensive Carry Discussions category; ...does that mean it will like it in JHP?
My gun seems to do well with the Federal FMJ I have been using for practice. ...

If you know your gun likes a certain brand in FMJ...

...does that mean it will like it in JHP?

My gun seems to do well with the Federal FMJ I have been using for practice. Can I rightfully assume that it will also shoot Federal JHP well? I'm wondering if I can confidently stick the JHP in for defense knowing the gun likes that brand, or if I should practice with it at the range with the JHP to make sure....

My gun seems to do well with the Federal FMJ I have been using for practice. Can I rightfully assume that it will also shoot Federal JHP well? I'm wondering if I can confidently stick the JHP in for defense knowing the gun likes that brand, or if I should practice with it at the range with the JHP to make sure....

It's all trial and error. HPs do not necessarily have the same shape as FMJs, even for the same bullet make. Try the Federal, if that's your choice, and see if it functions 100%. If not, another style or brand is in order.

My gun seems to do well with the Federal FMJ I have been using for practice. Can I rightfully assume that it will also shoot Federal JHP well? I'm wondering if I can confidently stick the JHP in for defense knowing the gun likes that brand, or if I should practice with it at the range with the JHP to make sure....

Signed, Clueless Newbie.

Unfortunately...no. There really isn't any correlation between the two...mainly because of the different bullet shapes.

But really, that shouldn't matter, as you should always test a carry load before greenlighting it.

I wouldn't be confident in any load unless I'd put at least a magazine or two through my pistol...usually, more like 100 rounds of it.

When I started firing my wife's new pistol, I tested my SD rounds in a cold, unfired gun. Then after firing about 50 rounds of range ammo rather rapidly (heating barrel), I test-fired more of the same SD ammo. Gun liked the SD ammo when it was hot and cold. I trust that ammo now and have bought a few more boxes of it. I will cycle it through the gun occasionally.

Absolutely not. Every ammo is different, and some guns simply won't easily swallow certain ammo, whether due to tolerances of the gun, or shape/length of the cartridge, or timing issues on the gun, or whatever. About the only way to know for certain is to shoot the jeebers out of it until you're certain, and even then there's still room for error.

Keep in mind that your gun is brand new, and it's not nearly broken-in yet. UNTIL THEN, it's hard to say what a given example of a gun (your specific one, in this case) is going to do, which might well be completely different than the next dozen examples you hear of via forums and word-of-mouth.

Particularly if you're experiencing bobbles from certain ammo, this is one of the reasons many of us typically do two things with a new pistol:

Shoot the gun through the full break-in period, at minimum, before worrying too much about this or that ammo. Of course, you need to shoot it, so you need to find a decent FMJ that'll work for that break-in shooting.

Once broken-in sufficiently to where it seems to swallow everything, then work hard to find a suitable defensive round that will meet your needs and that the gun seems to love. 'Cause, the last thing you want to happen is for that gun to get cranky when loaded with your defensive ammo in the unlikely event you find it necessary to defend yourself.

Examples:

My CZ P-01 9mm has been practically error-free. Though, with certain JHP ammo, it has cycled noticeably more smoothly and perfectly, as compared to any other JHP round. And as it turns out, the stuff it likes best is the longest (OAL) cartridge of anything I've tried. The longer the better. The gun's tolerances have just worked out that way. Couldn't have known that ahead of time, as I've read about a hundred other P-01's that reportedly worked just dandy with a wide variety of JHP. Mine has too, mostly, but it's darned near perfect with the DoubleTap JHP 124gr +P.

Another pistol I had years ago (a Browning BDM 9mm) swallowed everything without issue, after the initial break-in period. Cruddy rounds, discards, reloads, factory stuff, defensive rounds, JHP/FMJ/LFN/whatever. Yet, a second example of the BDM that I had years afterwards failed on many different JHP rounds, whereas nearly all FMJ was just fine. Go figure.

The point is: every gun is different, and some might have the tolerances just right (or wrong) such that certain ammo won't work well. At least, not until it's loosened up quite a bit. You'll need to test it, to find the "good stuff."

Lara: My P238 would shoot FMJ flawlessly but would not even chamber JHP, critical defense, and a couple others. I poished the ramp that directs the bullet into the chamber with a Dremel tool and now it works with all of the above. I called SIG on the problem and their answer was just to shoot it more. For a while I carried Pow-R-ball because it had the same profile of the FMJ and worked fine in my P238. Not only are individual bullets different, individual weapons of the same type may be different. A friend's P238 would fire all of the above right out of the box. I agree with the above comments that you need to find a bullet type that works flawlessly in your individual gun. Not only that the individual magazine may be different enough to cause trouble. Another thought: The FMJ is the only standard power .380 bullet that consistantly gets FBI/CIA gell minimum penetration.